I purchased the phone flat out on eBay about 5 or so months ago because I wasn't eligible for an upgrade and my Evo 3D was feeling more and more dated every day. It was a risk buying off eBay and at first it looked like I got scammed. Sprint would not activate it because it was tied to another account while the seller was adamant he bought the phone brand new and never activated it which I somewhat agreed because it came totally un-opened but Sprint just flat out wouldn't touch it. After a lot of calling we finally figured out because he ordered it online as an upgrade Sprint did in fact activate it but his account was in good shape so they let us switch ESN's. YMMV while buying a phone online so take caution out there that's just my story what happened to me but could have been a lot worse IE the phone was stolen or something.
I fell in love with the phone just using it a few seconds after powering it on. It felt just more fluid and responsive over my Evo 3D and the screen is just awesome. With 2GB of Ram and an alright 1.5GHZ Dual Core it takes a lot to slow the Galaxy S3 down and in fact outside of opening like 20 tabs threw Chrome I haven't been able to really make the phone stutter.I'm running the official 4.1.1 Update with Root nothing else added. Quadrant gave it a score of 6019 while Antutu Benchmark gave it a score of 11132 all averaged over 10 runs of each benchmark. The only let down hardware wise is the fact that the international version has the Exynos 4 Quad Core CPU but only 1GB RAM while the Korean version has both the Quad Core and 2GB of RAM so our US version is under powered by comparison. Battery life is good with the exchangeable 2100mAh battery. Under heavy usage like HD Gaming while streaming music I can usually get away with 4 or so hours before it finally bites the dust and more day to day usage with good cell phone signal and browsing the web listening to music I can usually get a full 12 hours out of it so it is rather impressive to me for such a slim phone. While we are on the subject of batteries Samsung showed off wireless charging when it debuted the phone and yet here we are in January with still no official Samsung one, yet there are I think is only one 3rd party that have a wireless charging kit for the S3. This is just a small annoyance but I was really hoping to buy one when I saw it in their debut but I have given up hope Samsung will ever release theirs.
I like the design of the Galaxy S3 with how slim it is so even though it has a fairly large screen it's not too brutal carrying it around in your pocket. Some people don't like the smooth plastic back and coming from an Evo 3D which had a nice textured back it is somewhat of a let down but I learned to live with it. It has a nice 8MP Camera in the back with a LED flash and a 1.9/2MP Camera in the front for video chatting. I don't video chat but I occasionally take pictures with the rear camera and as long as there is a decent amount of light I think it does just a fine job but it won't go replacing my DSLR anytime soon. While it does have a flash I find it rather pointless because it washes out all the pictures at night so I usually only ever use it as a flash light. It has a fairly decently loud speaker beside the flash module on the back of the phone but if you want to use speakerphone you have to basically place the phone screen down because placing it on the back covers the speaker. The phone is pretty durable you can risk dropping it but if it falls on a right spot it will crack like mine has but luckily I had insurance so they replaced it but if it falls on the back like mine has multiple times it does just fine. Lesson here though be careful with your expensive phones!!!
It was released with Android 4.0.4 with Samsung's "TouchWiz" interface on top and while some people don't like Touchwiz I actually really enjoy it. I don't use a lot of the features Touchwiz has but I respect that it has it. Samsung released their official Jellybean update I think in September or November even though Custom modders had it on the device only a few days after it was released. With Jellybean it really made the phone shine with Project Butter making just everything you do with it smooth. My favorite Touchwiz app by far is Samsung's built in video player. It can do everything you have seen it do in the commercials and I just think it's really cool to be able to pop out a video and go do something else while the video is still playing in a box right there on your screen. And that's not to mention that the video player will play nearly any file type I throw at it. Everything else like S-Beam and stuff I haven't really used because I'm the only one of my friends with a S3 so I got no one to tap phones with but I still think it's a neat idea.
And finally here is where we get to the elephant in the room at least for me. This was Sprint's basically "Flagship" LTE Phone yet for the longest time even after the phone's release there was no LTE. And even now they have started rolling out very very very limited markets with a complete rollout by the end of 2013. I'm in Seattle with no LTE signal what so ever and even in the markets there are LTE the speeds aren't exactly as fast as the other big 2. I'm holding out hope that when Sprint does complete it's LTE it will live up to my expectations because being stuck on their 3G is no fun. I'd rather have Dial Up than use Sprint's 3G at times so the phone is really handicapped unless you are on Wifi to do any sort of websurfing and music streaming.
Summing this phone up is hard. It is amazing to actually use while you are on Wifi but frustrating because of Sprint's 3G when you are not. The battery life is good, the screen is gorgeous, and it has plenty of storage with the ability to have even more storage. It could've been faster hardware wise, I don't buy into Samsung's reason that our LTE wouldn't work with the Exynos, but that's just the enthusiast in me wanting the best hardware because honestly the Dual Core and 2GB of Ram gets the job done with whatever you throw at it it's just the lack of Sprint's LTE that is really the disappointing thing.